Separator

A separator separates a first from a second phase of a liquid in a tubular container. The separator has a float made of elastic material having a circumferential sealing edge and at least one ballast fastened to the underside of the float. The density of the ballast is greater than the density of the float and the density of the entire separator lies in a value range between the density of the first phase and the density of the second phase of the liquid. In order to securely prevent penetration of parts of the second phase of the liquid into the region above the separator within the tubular container, when the separator moves into the sealing position and is positioned there, the sealing edge of the float is formed at a predetermined distance greater than zero above the center of gravity of the entire separator.